Multi-antenna system and electronic device thereof

A multi-antenna system, comprising a high-frequency operating frequency and a low-frequency operating frequency, wherein the multi-antenna system comprises:

• a conductive plane, comprising four adjacent sides;
• a main antenna unit, disposed on one of the four sides;
• a first secondary antenna unit, disposed on one of the four sides and apart from the main antenna unit by a spacing, wherein the spacing is greater than 0.5 times a wavelength of the low-frequency operating frequency;
• a second secondary antenna unit, disposed on one of the four sides except the side on which the main antenna unit is disposed;
• a switching circuit, disposed on the conductive plane and selectively electrically connected to the first secondary antenna unit or the second secondary antenna unit;
• and
• a wireless communications module, disposed on the conductive plane and electrically connected to the switching circuit and the main antenna unit, wherein
• when the switching circuit is electrically connected to the first secondary antenna unit, the main antenna unit and the first secondary antenna unit constitute a first antenna combination;
• when the switching circuit is electrically connected to the second secondary antenna unit, the main antenna unit and the second secondary antenna unit constitute a second antenna combination;
• and when a radio frequency signal is fed to the second antenna combination, a polarization direction of a radiation pattern generated by the second secondary antenna unit is orthogonal to a polarization direction of a radiation pattern generated by the main antenna unit.